Selecting Circuit - Estimate Box Resonances from the project editor menu checks your circuit for possible box resonances and outputs the frequencies at which they would occur to the Box Resonances dialog box. You must input the analysis controls (Sweeps page of the Circuit Settings dialog box) before you can estimate box resonances.
If no box resonances are found the message ''No box resonances predicted below or within the specified frequency sweep.'' is output to the dialog box.Box Resonances chapter in the Sonnet User's Guide.